Towed body for representing an airborne target

ABSTRACT

The invention relates to a tow body for representing a flying target by means of infrared flares, the infrared flares being situated on the rear of the tow body and being ejectable by the tow body and being pulled by the tow body by means of a reel-off towing cable during burning time. According to the invention, a drop unit ( 1 ) for the burned-up IR flares is arranged on the rear of the tow body, which drop unit ( 1 ) comprises a circular receiving unit ( 7 ) which is rotatably disposed and constructed under a retaining plate ( 8 ), for the towing cable nipples ( 17 ) forming the tow-body-side end of the towing cable, after the burning-up of an infrared flare, the corresponding towing cable nipple ( 17 ) connected with the infrared flare being released by a rotation of the receiving unit ( 7 ).

[0001] The invention relates to a tow body for representing a flying target according to the preamble of claim 1.

[0002] In manned flying target representation, tow bodies have been equipped for some time with infrared (IR) flares and have been used for training and bombarding by missiles equipped with infrared (IR) guidance heads. These IR flares can be obtained on the market with a wide spectrum of activity and can be fixedly fastened to the rear of the tow body.

[0003] For reasons of reusability of the tow bodies, however, the IR flares can also be pulled on reel-off towing cables behind the tow bodies, whereby, in the event of a hit of the missile, only the IR flare and not the tow body will be lost.

[0004] German Patent Document DE 28 50 220 C2 describes a drop unit for target bodies, in the case of which the target bodies are situated in a container fixedly connected with an airplane. One end of a towing cable is fixedly connected with the container. A transmission part is situated at the other end of the towing cable. The target bodies are connected by way of a connection cable with a coupling element. After a target body has been triggered, the coupling element constructed as a guide sleeve is guided by the towing cable until it has reached the transmission part. After the conclusion of the target representation, the coupling element is released by means of a mechanism, whereby the target body is dropped together with the connection cable.

[0005] Another tow body is known from German Patent Document DE 198 14 936 C1, in the case of which each IR flare is situated in an ejection unit and, during the ignition, is driven out toward the rear, and is pulled during the flaring period by means of a reel-off towing cable by the tow body. In this case, the towing cable is fixedly connected with the rear of the tow body. After the burning-up of the IR flare, the towing cable is cut by means of a cable cutter situated in the ejection unit. Together with its towing cable, the burned-up IR flare will fly off toward the rear. However, the pyrotechnic cable cutters normally used in this case were found to be cost-intensive and susceptible to disturbances and represent a significant risk source when the tow body is used.

[0006] Another demand on the drop unit is a high tensile loading of the tow-body-side fastening of the towing cable during the final braking of the IR flare falling into the towing cable.

[0007] It is an object of the invention to provide a tow body of the above-mentioned type which permits a risk-free and reliable dropping of a towed burned-up IR flare.

[0008] This object is achieved by means of the object of claim 1. The subclaims relate to advantageous embodiments of the invention.

[0009] According to the invention, a drop unit for the burned-up IR flares is arranged at the rear of the tow body, which drop unit comprises a rotatably disposed circular receiving unit (for example, a rotor) constructed under a retaining plate, for the towing cable nipples forming the tow-body-side end of the towing cable, in which case, after the burning-up of an infrared flare, the corresponding towing cable nipple connected with the infrared flare is released by rotating the receiving unit.

[0010] By means of the invention, a simple and operationally reliable dropping device is implemented for towed burned-out IR flares. It is ensured that, before the ignition of the respective next IR flare, the preceding burned-out IR flare is dropped. In this case, the dropping of the burned-out IR flare takes place without any pyrotechnic measures, whereby risk sources are avoided.

[0011] In an advantageous embodiment of the invention, the receiving unit has indentations for receiving the towing cable nipples. These indentations are advantageously constructed at a fixed distance from the center of the receiving unit. In particular, the indentations are arranged in a circular-symmetrical manner. In the retaining plate arranged above the receiving unit (viewed in the direction of the rear), a not completely closed, ring-shaped recess is advantageously constructed. In this case, the width of this recess is smaller than-the diameter of the towing cable nipples.

[0012] The receiving unit and the retaining plate are arranged with respect to one another such that the indentations in the receiving unit and the recess in the retaining plate are situated above one another in an aligned manner.

[0013] As a result of these measures, it is achieved that the towing cable nipples are held between the receiving unit and the retaining plate.

[0014] Another opening is advantageously constructed in the retaining plate, the diameter of this opening being larger than the diameter of the towing cable nipple. The opening can be constructed particularly at one end of the not completely closed ring-shaped recess. This permits the release of a towing cable nipple from the receiving unit precisely at the point at which the enlarged opening in the retaining plate is situated. As soon as the receiving unit is brought, for example, by rotation, into the position in which a towing cable nipple is situated in the enlarged opening of the retaining plate, the towing cable nipple will be thrown out of the receiving unit by the tension force caused by the towed IR flare. This permits a simple and reliable ejection of a burned-up IR flare without additional pyrotechnic measures.

[0015] For improving the ejection of the towing cable nipple, it is also possible to provide spring elements on the bottom of the indentations in the receiving unit. The spring elements are arranged such that the spring force points in the direction of the ejection opening. As a result, a promoting effect is achieved during the ejection of a towing cable nipple.

[0016] Thus, it may be necessary to drop the towing cable nipple of an IR flare which was ignited but was not ejected, for example, as a result of a malfunctioning. Since in this case no tension force acts upon the towing cable nipple, the nipple is ejected by means of the spring.

[0017] For driving the receiving unit, in particular, a strong electric motor is present (for example, an electric motor with a reducing gear on the input side). In this case, the receiving unit is fixedly connected with the drive shaft of the electric motor. Furthermore, a freely rotatable connection exists between the retaining plate and the drive shaft of the electric motor. As a result, a high stability of the retaining plate is ensured and a bending of the retaining plate caused by the tension force of an ejected IR flare is prevented.

[0018] In another advantageous embodiment of the invention, a microswitch is provided which has an intermittent sprocket. By means of the intermittent sprocket rolling off on the circumference of the rotor, the angular position of the rotor can be determined. The receiving unit can be brought precisely into the position in which an optimal ejection of the towing cable nipple is possible.

[0019] For improving the determination of the angular position, recesses can advantageously be constructed circular-symmetrically on the circumference of the receiving unit. The number of the recesses advantageously corresponds to the number of indentations for the towing cable nipples. During the rotation of the receiving unit, the intermittent sprocket can fall into one of the recesses, whereby a precise determination of the angular position of the receiving unit is possible.

[0020] Advantageously, an electronic control unit is provided by means of which the IR flares are ignited and can be ejected from the ejection unit of the towing body and can be dropped after the burning-up of the IR flares together with the towing cable. As a result, a reliable and faultless dropping of burned-up IR flares can be achieved.

[0021] In the following, the invention will be explained in detail by means of figures.

[0022]FIG. 1 is a sectional representation of the construction of a dropping unit according to the invention with a driving motor unit and a microswitch;

[0023]FIG. 2 is a view of an example of an embodiment of a receiving unit with indentations for the towing cable nipples and recesses for the intermittent sprocket of a microswitch as well as a retaining plate with a ring-shaped recess and an ejection opening for the towing cable nipples;

[0024]FIG. 3 is an enlarged representation of the drop unit of FIG. 1 according to the invention;

[0025]FIG. 4 is a top view of an example of an embodiment of the drop unit according to the invention.

[0026]FIG. 1 is a sectional view of the embodiment of a drop unit 1 according to the invention which has a driving motor 2 and a microswitch 3. In this case, the sectional plane extends along the longitudinal axis of the cylindrical tow body (not shown). The driving motor 2 and the drop unit 1 are spatially separated from one another by the rear plate 4 of the tow body. In the rear plate 4, a hole (not shown) is constructed through which the drive shaft 5 of the driving motor 2 is guided. By means of a fitting spring 6, the receiving unit 7 of the drop unit 1 is fastened on the drive shaft 5 and can thus be carried along. Viewed in the direction of the rear of the tow body, the retaining plate 8 is arranged above the receiving unit 7 and is connected, for example, by means of screws 19, with the rear plate 4. The retaining plate 8 may, for example, be an Al plate of a thickness of at least 4 mm.

[0027] On the right, FIG. 2 shows an example of an embodiment of a circular receiving unit 7 with six indentations 10 for receiving towing cable nipples and six recesses 11 for receiving the intermittent sprocket of a microswitch. An example of the retaining plate 8 with a not completely closed recess 13 and an ejection opening 14 for the towing cable nipples is illustrated on the left.

[0028] The circular indentations 10 are circularly arranged at a fixed radial distance from the center, adjacent indentations 10 forming an angle of 60° with respect to one another. The inside diameter of the indentations 10 may be as large or slightly larger than the outside diameter of the towing cable nipples, in which case the diameter of the towing cable nipples should be larger than the diameter of the towing cable.

[0029] The recesses 11 for receiving the intermittent sprocket of a microswitch are arranged on the circumference of the receiving unit 7. In this case, adjacent recesses 11 form an angle of 60° with respect to one another and are each arranged between two indentations 10. The recesses 11 may, for example, be milled and, depending on the rotating direction of the receiving unit 7, form a flat tapering-off toward one side. As a result, during the rotation of the receiving unit, an optimal rolling-off of the intermittent sprocket is achieved on the receiving unit 7. The receiving unit 7 illustrated as an example in FIG. 2 is designed for a levorotary operation.

[0030] The retaining plate 8 (left in FIG. 2) has a not completely closed circular recess 13. The diameter of this circular recess 13 corresponds to the diameter of the circularly arranged indentations 10 in the receiving unit 7. In addition, the width of the recesses 13 should be smaller than the diameter of the towing cable nipples 17 but larger than the diameter of the towing cable. As a result, the towing cable nipples 17 are held in the drop unit.

[0031] At one end of the recess 13, an ejection opening 14 is constructed whose diameter is larger than the diameter of the towing cable nipples 17. As a result, a reliable ejection of the towing cable nipples and thus of the burned-up IR flares is achieved. The ejection opening 14 is arranged corresponding to the rotating direction of the receiving unit 7. In FIG. 2, the ejection opening 14 is constructed, as the result of the left-hand rotation of the receiving unit 7 on which it is based, at the rearward end of the recess 13. When a right-hand rotating receiving unit 7 is used as the basis, the ejection opening 14 should be constructed at the forward end of the recess 13. The recess 13 constructed in the retaining plate 8 and the ejection opening 14 are therefore used as an ejection backdrop for the towing cable nipples.

[0032] The receiving unit 7 and the retaining plate 8 are arranged on the drive shaft (not shown) such that the ejection opening 14 and an indentation 10 are aligned above one another. As a result, an indentation 10 is moved under the ejection opening 14 during each rotation of the receiving unit by 60°, whereby a reliable ejection of the towing cable nipples is achieved.

[0033]FIG. 3 is an enlarged cutout of the drop unit 1 from FIG. 1. In the indentations 10 of the receiving unit 7, spring elements 12 are arranged for receiving the towing cable nipples 17. These spring elements 12 have the purpose of ensuring a reliable dropping of the towing cable nipples 17 in the event that no tension force acts upon the towing cable nipple 17, for example, as a result of a defective and not ejected IR flare.

[0034] The central area of the retaining plate 8 is connected, for example, by means of a screw 16 with the receiving unit 7. Although, in this case, the screw 16 is fixedly connected with the receiving unit 7, it is freely rotatable on the retaining plate 8. As a result, a supporting of the central area of the retaining plate 8 is achieved by way of the receiving unit 7 to the outer area of the retaining plate 8, in which the retaining plate 8 is connected with the rear plate of the tow body. When the IR flare is ejected and the tensile load onto the towing cable nipples is therefore high, a bending of the central area of the retaining plate 8 is therefore prevented.

[0035]FIG. 4 is a top view of the ejection device 1 according to the invention with the microswitch 3. In this case, the indentations 10 are provided with five towing cable nipples 17. By means of the screws 19, the retaining plate 8 is fixedly connected with the rear plate of the tow body. The microswitch 3 is illustrated with the intermittent sprocket 18 in two positions. In the following, the upper switching position is the position in which the intermittent sprocket 18 is situated in the recess 11. When the intermittent sprocket 18 rests on the circumference of the receiving unit 7, the microswitch 3 is in the lower switching position.

[0036] By means of the two switching positions of the microswitch 3, it is now possible to implement a defined operating sequence by means of an electronic control unit (not shown). The operating sequence comprises the ignition of an IR flare with a subsequent ejection as well as the ejection of the burned-up towed IR flare. In this case, the electronic control unit should comply with the following operating sequence:

[0037] After the pilot has ignited and ejected an IR flare by way of the control unit, an internal timer is started which, during the entire burning duration (approximately 70 seconds) of the IR flare, prevents any intervention in the operating sequence of the control unit. As a result, it is prevented that an unintentional dropping of a burning towed IR flare takes place. In addition, the premature ignition of a second IR flare is prevented before the previous IR has been dropped.

[0038] After the burning of the IR flare is concluded, the possibility of the dropping of the burned-up IR flare is indicated to the pilot, for example, by way of a display. When the flare drop is activated by the pilot at a point suitable for him, a time-limited voltage signal (approximately 1 second) is applied to the driving motor. In this case, the driving motor rotates the receiving unit 7 by a slight angle, for example, 30°.

[0039] By means of the intermittent sprocket 18, the microswitch 3 is moved from the upper switching position into the lower switching position, which activates the microswitch 3. The microswitch 3 will maintain the voltage supply to the driving motor (parallel connection) until the intermittent sprocket 18 falls into the next recess 11. In this case, the microswitch 3 is moved from the lower switching position into the upper switching position, whereby the voltage supply to the driving motor is interrupted. As a result of this measure, it is ensured that the driving motor rotates the receiving unit 7 precisely by 60° and in the process brings an indentation 10 precisely under the ejection opening 14 of the retaining plate 8.

[0040] The dropping of the burned-up IR flare is indicated to the pilot, for example, by means of a display. Simultaneously, the control unit will be released for the ignition of the next IR flare. This processes can now be repeated to the last IR flare, in the present example, to the fifth IR flare. 

1. Tow body for representing a flying target by means of infrared flares, the infrared flares being situated on the rear of the tow body and being ejectable by the tow body and being pulled by the tow body by means of a reel-off towing cable during burning time, characterized in that a drop unit (1) for the burned-up IR flares is arranged on the rear of the tow body, which drop unit (1) comprises a circular receiving unit (7) which is rotatably disposed and constructed under a retaining plate (8), for the towing cable nipples (17) forming the tow-body-side end of the towing cable, after the burning-up of an infrared flare, the corresponding towing cable nipple (17) connected with the infrared flare being released by a rotation of the receiving unit (7).
 2. Tow body according to claim 1, characterized in that indentations (10) for receiving the towing cable nipples (17) are constructed in the receiving unit (7) at a fixed distance from the center, and a not completely closed ring-shaped recess (13) is constructed in the retaining plate (8), the width of the recess being smaller than the diameter of the towing cable nipples (17).
 3. Tow body according to claim 1 or 2, characterized in that an opening is constructed in the retaining plate (8) whose diameter is larger than the diameter of the towing cable nipples (17).
 4. Tow body according to one of the preceding claims, characterized in that the angular position of the receiving unit (7) can be detected by means of an intermittent sprocket 18) of a microswitch (3) rolling off on the circumference of the receiving unit (7).
 5. Tow body according to claim 4, characterized in that recesses (11) for receiving the intermittent sprocket (18) are constructed on the circumference of the receiving unit (7), which recesses (11) are assigned to the individual indentations (10).
 6. Tow body according to one of the preceding claims, characterized in that a driving motor (2) is provided for driving the receiving unit (7).
 7. Tow body according to claim 6, characterized in that the power supply of the driving motor (2) and the microswitch (3) are connected in parallel.
 8. Tow body according to one of the preceding claims, characterized in that an electronic control device is provided by means of which the IR flares are ignited and can be ejected from the ejection unit of the tow body and, after the burning-up of the IR flares, can be dropped with the towing cable.
 9. Tow body according to one of the preceding claims, characterized in that, for promoting the ejection of the towing cable nipples (17), spring elements (12) are provided in the indentations for receiving the towing cable nipples (17), which spring elements (12) have a force acting in the direction of the retaining plate (8). 